1. Field of the Invention
The present invention is generally related to a watercraft braking system and, more particularly, to a control mechanism for a jet propelled watercraft that provides a hydrodynamic assist device which facilitates either the engagement of the brake or the disengagement of the brake, or both, when the brake is actuated by an operator of the watercraft.
2. Description of the Prior Art
Jet propelled watercraft have been used for many years, and many types of jet propelled watercrafts are well-known to those skilled in the art. It is also well-known to provide a reverse gate, which is sometimes referred to as a reverse bucket, for the purpose of allowing the watercraft to move in a reverse direction. In certain circumstances, the reverse gate can be used to perform a braking function to slow and stop the watercraft, but the use of a reverse gate for the purpose of braking a watercraft is not generally advised with many known systems because of several disadvantages that exist in known reverse gate systems.
U.S. Pat. No. 5,551,898, which issued to Matsumoto on Sep. 3, 1996, discloses a discharge nozzle arrangement for a waterjet propulsion unit. Several embodiments of the device are described in relation to the steering nozzle and reverse thrust bucket for the jet propelled watercraft. The steering nozzle, in addition to being mounted for steering movement about a vertically extending steering axis, is also mounted for trim adjustment about a horizontally extending axis. A cooperating reverse thrust bucket provides reverse thrust operation. The reverse thrust bucket is either mounted on the hull of the watercraft independently of the jet propulsion unit, on the outer housing of the jet propulsion unit independently of the steering nozzle, or on the steering nozzle.
U.S. Pat. No. 5,344,344, which issued to Forsstrom on Sep. 6, 1994, describes a steering and reversing system for a marine jet propulsion unit. The system has a stationary nozzle for discharging a waterjet rearwardly from the unit and comprises a pair of steering and reversing members that are mounted side by side at the rear end of the nozzle and individually pivotable in opposite directions about upright axes from a non-deflecting position to first and second deflecting positions. In the non-deflecting position, the steering and reversing members form a rearwardly directed extension of the nozzle, while in the first deflecting position each member diverts a portion of the waterjet laterally outwardly by means of its front section. In the second deflecting position each member deflects a portion of the waterjet downwardly and forwardly by means of scoop-like members at its rear section.
U.S. Pat. No. 3,937,172, which issued to Castoldi on Feb. 10, 1976, discloses a waterjet propelling apparatus for boats. The apparatus forces water by a pump through a nozzle directed a stern of a boat. A curved jet-deflecting surface downwardly and forwardly deflects the water and reverses the thrust, and a pair of steerable parallel rudder blades are pivotable in unison for laterally deviating the jet. The jet-deflecting surface has symmetrical channel-like side portions which direct water escaping laterally from the clearance between the trailing edges of the rudder blades and the jet-deflecting surface forwardly towards the bow to enhance the reverse thrust, and a central portion which is shaped with blades for maintaining the clearance with the later constant for various pivotal deviations of the blades.
U.S. Pat. No. 5,622,132, which issued to Mardikian on Apr. 22, 1997, describes a shock absorbing steering system for a personal watercraft. The improved steering assembly for a personal watercraft governs the positioning of a steering nozzle through a cable that is affixed to a steering shaft attached to handlebars gripped by the operator of the watercraft. The steering shaft is mounted to the hull in a retainer member relative to which it is rotatable. The handlebars are shielded from the shocks and bumps occurring while the watercraft travels on rough water by a shock absorber that is mounted between the retainer member and the handlebars. The improved steering assembly significantly increases riding comfort and reduces operator fatigue.
U.S. Pat. No. 5,193,478, which issued to Mardikian on Mar. 16, 1993, describes a system for trimming, steering and braking a watercraft which includes a retractable plate or flap disposed on each lateral side of the hull of the watercraft. Each flap is extendible into the water, rearwardly in a continuously adjustable manner, and independently of the extension of the other flap. When the flap is fully extended, its angular position relative to the hull is also continuously adjustable independently of the angular positioning of the other flap. The flaps in their fully declined position act as powerful brakes for the watercraft. The differential extension of the flaps or differential adjustment of the relative angular positions on the two sides of the watercraft results in trimming and steering of the watercraft.
U.S. Pat. No. 5,092,260, which issued to Mardikian on Mar. 3, 1992, discloses a personal watercraft with brakes. The watercraft such as a jet ski is equipped with a hull, engine, propulsion and ride plate assembly which is attached to the bottom section of the hull. The ride plate assembly includes a fixed plate and a lower plate or flap hingedly mounted to the fixed plate to occupy continuously adjustable varying angular positions relative to the fixed plate. A manually operated control mechanism, controlled by an operator, adjusts the angular positioning of the flap within a pre-determined range. It is an important characteristic of the continuously adjustable flap that, within the range in which its angular positioning relative to the fixed plate and of the water can be changed, an initial and moderate change in angular positioning results in more hydrodynamic lift to act on the watercraft and therefore an increased speed of the watercraft. However, beyond a certain value, further deflection of the flap results in significant braking action. In another embodiment of the watercraft, braking of the watercraft is accomplished by mechanically braking the shaft which connects the engine with the propulsion system. This is accomplished by placing mechanically or hydraulically actuated brake pads in operative engagement with a rotating shaft or with a rotating disc fixedly mounted to the shaft. The brakes slow down the rotation of the propulsion system and therefore the entire craft, significantly faster than mere release of the throttle, as is done in the prior art.
U.S. Pat. No. 5,607,332, which issued to Kobayashi et. al. on Mar. 4, 1997, discloses a control system for a jet powered watercraft. A number of embodiments of jet propelled watercraft have an improved pedal operated reverse thrust bucket mechanism. The pedal for operating the reverse thrust bucket is positioned so that it is generally flush with the floor area when the reverse bucket is in its forward drive mode and can be depressed into a recessed area of the floor area for effecting trim or reverse thrust operation of the reverse thrust bucket. In this way, the pedal does not obscure the rider's foot area but is still readily accessible for the rider.
U.S. Pat. No. 5,551,898, which issued to Matsumoto on Sep. 3, 1996, describes a discharge nozzle arrangement for a waterjet propulsion unit. A number of embodiments of the steering nozzle and reverse thrust bucket arrangements for jet propelled watercraft are described. The steering nozzle, in addition to being mounted for steering movement about a vertically extending steering axis, is also mounted for trim adjustment about a horizontally extending axis. A cooperating reverse thrust bucket provides reverse thrust operation. The reverse thrust bucket is either mounted on the hull of the watercraft independently of the jet propulsion unit, on the outer housing of the jet propulsion unit independently of the steering nozzle, or on the steering nozzle.
U.S. Pat. No. 5,299,960, which issued to Day et. al. on Apr. 5, 1994, describes an auxiliary water projector for a jet propelled watercraft. The projector system only requires removal of the steering nozzle in order to be connected to the waterjet propulsion system. A thrust control valve is positioned adjacent to the remounted steering nozzle. Using the thrust control and a flow control valve, the operation of the watercraft and auxiliary water projector can be simultaneously controlled to include stationary, forward or reverse movement of the watercraft.
U.S. Pat. No. 5,752,864, which was filed by Jones on Jan. 16, 1997 and assigned to the assignee of the present invention, discloses a reverse gate for a personal watercraft. The reverse mechanism includes a reverse gate that provides low restriction to the flow of water through the jet pump and also provides significant steering characteristics. The reverse gate has a deflector surface with a vertical jet divide that divides the deflector surface. Both sides of the deflector surface are in the form of a simple curve. In the preferred embodiment, the simple curve deflector surfaces slant inward towards a central apex which serves as the vertical jet divide. The deflector surface spans between a starboard side support structure and a port side support structure which are pivotally mounted along a horizontal axis so that the reverse gate can be moved between a full-up position and a full-down position rearward of the jet pump. Both the starboard side support structure and the port side support structure include apertures therethrough which allow a portion of the jet flow to exit laterally from the reverse gate. When the reverse gate is in the fully down position, a portion of the jet flow is redirected forward to provide reverse thrusts. A portion of the jet of water is deflected laterally to port and laterally to starboard proportionally in accordance with the direction of the jet pump rudder.
U.S. Pat. No. 5,755,601 which was filed by Jones on Mar. 17, 1997 and assigned to the assignee of the present invention, discloses a brake system for a personal watercraft. The watercraft has a brake which the driver of the watercraft can use to decelerate the forward motion of the watercraft. The brake mechanism preferably includes a reverse gate that allows steering to be consistent when the watercraft is accelerating or cruising with the reverse gate in a full-up position as when the watercraft is decelerating with the reverse gate in a full-down or partial-down position. The positioning of the reverse gate during operation of the watercraft is adjusted in accordance with the state of hand operated actuators for a forward throttle control mechanism and a brake control mechanism. Preferably, an electronic controller receives a signal from the control mechanisms and outputs a control signal that directs a servo motor to move a reverse gate control cable or linkage to position the reverse gate. Forward thrust can be increased by proportionally closing the actuator for the forward thrust control mechanism. In addition, reverse thrust or braking thrust can be increased by proportionally closing the actuator for the brake control mechanism.
Many types of reverse gate mechanisms can possibly be used as a brake to slow the speed of a watercraft, but for various reasons this is not always easily accomplished. For example, in watercraft that use a lever mounted on the side of the hull to actuate the reverse gate, the operator must release his or her grip on the handlebars in order to reach down to the reverse gate lever. In addition, because of the magnitude of the hydrodynamic forces involved in the movement of a reverse gate into the outlet stream of water being ejected by the jet pump, it is typically necessary to provide an actuating lever with a sufficiently long arm to allow the operator to have sufficient leverage to more easily overcome the forces which tend to resist the actuation of the brake when the engine of the watercraft is operating at a significant speed.
Another reason why reverse gates are not intended for use as brakes for personal watercraft is that most reverse gates are not sufficiently robust to withstand the rigors of use in this manner. The forces created by the stream of water flowing out of a jet pump nozzle can damage the reverse gate if it is repeatedly operated while the engine of the watercraft is operating at full power. Although certain reverse gates may be sufficiently rugged to withstand this type of use, it still requires a significant physical effort to engage the brake while the watercraft is operating at a relatively high speed. It also requires a significant operator effort to disengage the brake when the engine is operating at a relatively high speed.
It is clearly desirable to provide a hand operated brake which does not require the watercraft operator to release the grip on the handlebars for the purpose of actuating the brake. For example, it would be highly desirable to provide a brake actuation lever similar to the types of brake levers used on motorcycle handlebars. This would allow the operator to actuate the brake by merely extending the fingers over the lever and squeezing the lever to move it relative to the handlebars. In this way, the mere tightening of the operator's grip is sufficient to actuate the brake. However, as will be described in greater detail below, the hydrodynamic forces created by the ejected stream of water from the jet pump as the water impacts the deflecting surface of the gate can be sufficiently high to prohibit the effective and quick operation of the brakes through the use of the operator's fingers alone. It would therefore be significantly beneficial if a control mechanism could be provided for a jet propelled watercraft that allows an operator to actuate the brake with only the force of his or her hand gripping the handlebars, but would also allow the brake to be disengaged with an approximately or equal amount of hand force.